Grounding fitting



1933-1 s. N. BUCHANAN GROUNDING FITTING Filed July 26, 1929 anomwozSTEPHEN MBw/M/W luv mung

III

Patented Feb. 28, 1933 UNITED STATES PATENT] o mcE. A

STEPHEN N. BUCHANAN, OF ELIZABETH, NEW JERSEY, .ASSIGNOR TO THE THOMAS &BETTS 00., OF ELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEYGROUNDING FITTING.

Application filed July 26, 1929; Serial No. 881,118.

on a water pipe or other ground conductor and shows an armored cableconnected to the fitting to enclose a ground wire, the cableitself beinginsulated from the fitting, but the ground wire in the cable iselectrically connected to the fitting.

Figure 2 shows a side view of Figure 1 as taken on the line 2-2 andshows a side view of the swivelled and insulated cable connecter. Fi re3 shows a face view of the groundmg. tting from the opposite side ofFigure 1 and illustrates the ground conductor such as a water pipe indotted lines. This view shows the device provided with a plurality ofpipe groove seats graduated in size for making an electrical groundconnection with water pipes of .difierent diameter.

This invention relates to electrical connecting devices and moreparticularlyto grounding fittings for establishing a ground wire orelectrical connection inhouse and building wiring systems to render thesame safe by grounding oil and transmitting away stray current or shortcircuits to the ground through a water or gas pipe or other availableconductor leading to the ground.

An object of the invention is to produce an improved grounding, fittingincluding means to establish a positive electrical connection withawater pipe or other similarly grounded conductor, as well as provideinsulated anchorage means by which to attach to the fitting a groundwire protective covering such as an ordinary flexible metal armoredcable,

and also to provide a suitable ground wire terminal connecter on thefitting, whereby the ground wire but not the armored cable may beelectrically connected or grounded to said fitting and hence to theplpe.

A particular object of the invention is to produce a grounding fittingwherein the usual armored cable may be insulated from the ground fittingand in this way the ground wire installation itself is rendered safe forthe reason that [current is not permitted to flow through the spiralarmored cable since the latter, being a poor conductor of current, wouldheatand increase the fire hazard should current fiowtherethrough due toa break down or short circuit somewhere in the ground wiringinstallation.

A further object is to produce a grounding fitting having a cableconnecter associated therewith, which connecter is insulated asaforementioned from the fitting and hence from the water pipe or othergrounded conductor, and a pivotal connection may be used if desired toattach the insulated cable connecter to the grounding fitting.

\Vith the foregoing objects and others-in view. theinventionhas-relation to certain combinations and arrangements of theparts, examples of which are disclosed in the accompanying drawing,wherein:

Figure 1 shows a plan rear face view of the 53 grounding fittingattached to and grounded 4-4 of Figure 1 to illustrate one example of acombination insulator and swivel attachment on the grounding fitting tomount a cable connecter thereon.

Figure 5 is a section on the line 55 of Figure 4 showin parts of thecombination insulated swivel y which a cable connecter is carried on theground clamp fitting.

Figure 6 is a side elevation of a modified form of insulated andswivelled or pivoted bracket to which an ordinary or standard form ofcable'connecter used in outlet boxes may be attached.

In the installation of wiring systems in houses, buildings and the likefor general lighting or power work, there is usually available a groundconductor such as a water or gas pipe P to which the electrical groundwire system may be electrically connected or grounded to render the samesafe by transmitting to the ground short circuits or other stray currenIn this connection the contractor installing the ground wire Wfrequently employs a flexible metal armored cable BX, itself a poorelectrical conductor, in which is carried the ground wire, one end ofwhich is adapted to be electrically connected'with the pipe 1? and theother end to an outlet box or other part of the main wiring system notshown. Primarily, the urpose of this invention is to provide groun ingfittings or connectors by which that end of the 1 Figure 4 is anenlarged section on the line t ground wire W shown in the drawing andcarried in the cable BX may be electrically connected or grounded to anyavailable size pipe P so that the wire 1V and pipe P may carry away tothe ground any stray potential existing in the main wiring installationnot shown. Furthermore a feature which char acterizes this invention isthe insulation means carried on the grounding fitting by which the cableBX, of poor conductivity, is insulated from the grounding fitting andfrom the pipe P so that the cable protecting the ground wire may notcarry current and become hot due to a break down or failure somewhereeither in the main wiring or circuit system or the ground wire.

Referring now to the drawing for a more detailed description of theinvention, there is shown a pipe clamp which embodies the featuresconstituting this invention. This pipe clamp comprises a yoke havingthreaded legs 8 carried on a yoke arch 9 which reaches over and clampsto the grounded water pipe P. A pipe seat 10 performs the function of aclamp strap to reach across the pipe in opposition to the arch 9 andthis seat 10 may be made in any suitable form such as that shown in thedrawing where a disc or circular pipe seat 10 is shown. However, thepipe seat or clamp strap 10 may be made square, rectangular or otherwiseshaped depending on convenience of manufacture and requirements to befilled. A nut 11 acts as clamp operating means and threads on each leg 8to grip the clamp 9-10 against a water pipe or other ground conductor.

\Vhile the pipe seat 10 may be made in various forms, one preferredembodiment thereof shown in the drawing and is suflicient to illustratethe principles of the invention. This pipe seat 10 is provided with anumber of yoke receiving holes in pairs 13, and 21 made in the peripherythereof and these holes are appropriately arranged in respect to groovedand toothed pipe seats formed in that face of the pipe seat or strap 10which is adjacent the yoke arch 9. Pipe receiving grooves 15, 16 and 17of different standard pipe sizes are made in the pipe seat 10 and theembodiment shown is merely one example of this structure. As a matter offact, three pipe seat grooves 15. 16 and 17 are shown and are related tothe three pairs of holes 13, 20 and 21 but any. suitable number ofgrooves and holes may be provided.

he pipe receiving grooves 15, 16 and 17 are arranged angularly inrespect to each other and the longitudinal axis of each groove passesthrough the center of the circular disc 10. This construction affords amaximum length for each groove and hence maximum contact making capacitywith the pipe in the groove to be selected according to the size of pipeavailable. By centering each pipe seat groove at the center of the seat10 itself, it is seen that each groove 15, 16 and 17 occupies thegreatest dimension of the member and hence the advantage of arrangingthe longitudinal axis of the plurality of grooves coincident with theaxis of the pipe seat 10. 4

As heretofore mentioned, two holes 13 that is a pair 13 are made in theperiphery of the pipe seat 10 and these holes are isposed rightangularin respect to, say the smaller pipe seat contact groove 15. There arealso shown and oppositely arranged the pair of holes 20 cooperating withthe pipe seat groove 16. In the same way there is shown the third pairof holes 21 arranged transversely t0 the larger pipe seat 17. Theseveral holes spaced about the pipe seat 10 are therefore arranged inpairs and in a plane passing through the axis of the seat 10 andtransverse to the longitudinal axis of the several pipe grooves withwhich the clamp 9-10 engages the pipe P.

An important feature of the invention relates to a characteristicanchorage means used to attach the cable BX to the pipe clamp 910. Thisanchorage means performs two purposes, that of insulating the cable BXfrom the grounding fittings 9-10 and that of affording an adjustableswivel attachment, whereby the cable BX, in which the ground wire WV isenclosed, may be insulated from and attached to the grounding fitting,regardless of the direction in which said cable BX extends. cable BX mayapproach the grounded pipe or conductor in a direction parallel to thepipe P or in some angular relation thereto, but such a condition mattersnot for the reason that the anchorage device swivels on the groundingfitting 910 to make convenient the sim le operation of attaching thecable to the tting.

A swivel arm or bracket 24 carries an insulated anchorage on one end toattach it to the ground fitting and a cable connecter on the other end.Describing first the cable connecter end and one form of cable connecterby which the cable BX is attached to the bracket or arm 24, it is seenthat the connecter may be constructed in any suitable form, and theexample shown merely explains the principle of the invention. Thebracket 24 in this instance carries a sleeve 25 made on its outer endand the sleeve receives the end of a cable BX thereinto. A screw 26 orother clamp means fastens the cable in the sleeve 25 and hence attachesthe cable to the grounding fitting by a swivel insulator laterdescribed. The cable connecter simply comprises the screw 26 whichloosely fits through a clamp yoke 27 and the screw 26 threads into a rib28 formed on the sleeve 25. The yoke has its parallel legs 27 slidableup and down through an opening formed through the sleeve wall 25 on eachside of the In other words, the

includes'a central perforation 32 :by'which to rib 28. In this way, thescrew causes the inner ends of thezyoke 27 to grip thecable and anchorthelatter inIthe connectersleeve 25. The ground wire LV islead throughthe cable BX and through its connecter or anchorage: means 25 and hasits free end stripped ofits insulation at 38 and coiled fit. the eye 30over one of the clamp legs 8.

The nut 11 is then-tightened up toanchor the eye bracket'2430 to thegrounding fitting. It is readily seen that the cable connecter may nowbe adjustably swiveled about the clamp leg 8 in order to line up thecable connecter sleeve 25 with the cable BX- In some forms of'constructiomit is very desirable or even necessary to insulate thecable BX and its connecter25 from the grounding fitting 9-10. For thispurpose, the connecter eye has its perforation 32 somewhat enlarged soasto receive a sleeve insulator 33 formed 'on'a washer insulator flange34. In other'words, the insulator 3334 is a bushing made of any suitablein sulating material such as'hard rubber or fibre. The insulationbushing 33-34 is first placed on the clamplegj8 with the washer flange34 in engagement with the pipe seat 10, and then the bracket eye 30 isplaced over the insulator. The bracket eye 30 and its attached parts arethereforepositively insulated'from the pipe seat lOand leg 8.-

After assembling the bracket eye 30 and insulator bushing 33-34 on'thegrounding pipe clamp, an additional insulator,'in theform of a plate orwasher 36, may beplaced over the metal eye 30 and over the gasket sleeve33, whereupon a metal washer 37 is'placedover the threaded leg 8 andagainst the insulator parts. The bare end 38 of the'ground wire is nowcoiled around the leg-8 of the clamp and against the metal washer 37,thelatter being cup shaped and including a flange 39 if desired to makea closed space in which the wire-end 38 is coiled. Another washer '40may be placed over the wire 38 and the nut 11 is then tightened up toanchor all parts together. 7

The metal bracket 24 and cable connecter is thus insulatedfro'm theground pipe and also swivels about the leg 80f the ground clamp orfitting. Figure?) shows a face view of the metal contacting washer40.adapted to be pressed toward the underneath metal washer 37, both ofwhich are spaced apart by reason of the wire 38 placedutherebetween',and the two views, Figures 4and .5, illustrate one example of thiscombination swiveled and insulated cable connecter for ground fittinguse. The two washers 37 and 40 provide a positive electrical connectormounted on the yoke legand electrically connected thereto buttinsulatedfrom the bracket arm "24 and eye 30. Hence the inner end of the arm 24carries a combination insulation and electrical connecter, the currentfrom thewire W having a good conductive path through the washer 40 andnut 11 into theyoke 8.

Figure 6 shows a side elevation of a, modified form of cable connecterwherein the eye 30 rests against an insulation bushing 34 and underneathan insulation washer 36 and thus it is similar in form to the devicesdescribed in Figures 4 and 5. However, the eye 30 carries an arm 43.which may be turned up at 44 and perfogated at H to make a standard sizehole to receive any suitable form of cable conneoten Thus I haveillustrated one, type of cable connecter at 25 and another simple formof cable connecter at44. p The principle of the invention is susceptibleto various forms of eonsiruction. The cable connecter arm 44 has itshole :H of the same size as an ordinary knockout in outlet boxes so thatany cable connecter may be used.

- It is seen that one. operating means, such as the nut 11 performs allfunctions of gripping the ground fitting on a pipe, locking the pivotagainst'rotation, and making electrical connection between the groundwire and pipe P; and that the pipe seat 10 can be rotated about theclamp legs 8 and have any of the seat holes 13, 20 and 21 mountedthereon. .It is significant that the metal eye or swivel head 30 isclamped between two in sulator means 34 and 36, and that the wire Iterminal 38 is clampled between two contact plates 37and 40. ence themetallic cable connecter 25 and its arm 24 and the swivelled eye 30,together-with the cable BX, are all positively insulated from the groundpipe P and the fitting 9-10 clamped and grounded thereon; but the groundwire W38 'is electrically connected to and thus grounded on the pipe andfitting.

The invention fills a need andenables one to safely use flexiblemetallic armored cable in ground wire installations.

What is claimed is: V

1. In a grounding fitting, a clamp having means to grip a groundconductorand make electrical connection therewith, anchorage means toengage and hold a ground wire protective covering, pivot means toadjustably attach the anchorage means to the clamp so that saidanchorage means may be pointed in anydirection desired to convenientlytach the protective covering to the clamp, and an insulator associatedwith the pivot means whereby the'protective covering is insulated fromthe clamp. i

2.- In a grounding fitting, a ground clamp having means to grip agroundconductor and make electrical Connection therewith, anchoragemeans to engage and hold a ground wire protective covering, pivot meansto adjustably attach the anchorage means to the clamp, an insulatormounted on the pivot means to insulate the protectivocovering fromtheground clamp,an electrical conductor extending thru the insulator toground a wire on the clamp; and a single operating means to grip theclamp on a pipe, to ip the ground wire to the conductor, an? to lock thepivot means against motion.

3. In a grounding fitting, a clamp having means to grip a groundconductor and make electrical connection therewith, a cable an choragemeans to attach a cable to the clamp, pivot means adjustably mountingthe cable anchorage means to the clamp, means to electricallyconnectaground wire in the cable to the clamp, and means insulating thecable from said clamp.

4. In a grounding fitting, a clamp having 'means to grip agroundconductor and ,make

electrical connection therewith, a cable anchorage means to attach acable to the clam pivot means to adjust-ably mount the cable anchoragemeans to the clamp, means to electrically connect a ground wire in thecable to the clamp but to insulate the cable from said clamp, said lastnamed means including a a swivel head clamped between two insulatormeans and a wire terminal clamped between two contact plates, and screwthread operating means to tighten the last named means.

5. In a grounding fitting, a ipe clamp having means to grip a groun ipeconductor and make electrical connect1on therewith, cable connectormeans to engage and hold a ground wire protective covering, means toadjustably attach the.

cable connector to the clamp, said pipe clamp including an operatingmeans to work the clamp and to fix the adjustable means in finallylocked position, insulatin means having two spaced parts associatec withthe operating means, and the adjustable means being mounted between thespaced parts, and an electrical connector mounted on the insulator andalso including two spaced parts between which a ground WII'B is gripped.r

6. In a grounding fitting, a clamp having means to grip a groundconductor and make electrical connection therewith including a -pipeseat and yoke having legs and nuts on the legs, anchorage meansmounted-on one or the yoke legs to engage and hold a ground Wll'eprotective covering, an insulator on the same leg to insulate thecovering from the fitting, and an electrical connecter on the leg toground a wire to said leg.

7. In a grounding fitting, a clamp having means to grip a groundconductor and including a yoke with threaded legs on which is mounte apipe strap, a swivel e e on the yoke, a cable connector carried'by t eswivel eye, and nuts on the legs to grip the swivel eye; on the clampand to ground the clamp on the conductor. y 8. In a rounding fitting, apipe clamp having a disk which is grooved across its center a number oftimes at different angles to form pipe seats of different sizes, anumber of holes in the disk, a yoke having legs thru theholes, aninsulator mounted on one of the legs and engaging the disk on the facethereof opposite the grooved seats, a cableconncctor mounted on theinsulator, an electrical connector mounted on the leg adjacent theinsulator and to which a ground wire is connected, a nut on eachleg togrip the pipe clamp on a ground conductor and to fasten the cableconnecter to the fitting and to render effective the electricalconnector.

9. In a grounding fitting, clamp means to ground on a pipe, an armmounted on the clamp means, ac-able connector carried on one end of thearm, an electrical connector carried on the other end of the arm wherethe latter is mounted on the clamp means to connect a ground Wire from acable secured in the cable connector, and insulating means insulatingthe arm from the clamp means.

10. In a grounding fitting, clamp means to ground on a pipe, an armpivotally mounted on the clamp means, a cable connector carried on oneend of the arm, an electrical connector carried on the other end of thearm where the latter is mounted on the clamp means to connect a groundwire carried by a cable secured in the cable connector to the clamp,insulating means insulating the arm from the clamp, and a single nut tolock the arm against pivotal motion after the latter is adjusted inrelation to the pipe, to render eifect-ivethe electrical connector, andto Work the clamp means.

I 11. 1n a pounding fitting, clamp means to electrically ground on arounded conductor, and a bracket mounted on the clamp means andincluding means at one end to attach a cable thereto and means at itsother end to pivotally mount the bracket on the clamp means, 'said lastmeans includinga pivotal insulator. and swivel eye to insulate thebracket from the clamp means, an electrical connecter included in andextending thru wire protective covering, pivot means to adjustablyattach the anchorage means to the clamp so that said anchorage means maybe pointed in any direction desired to conveniently attach theprotective covering to the clamp, an insulating bushing slidable androtatable upon the clamp and having a flange projecting therefrom, thepivot means being received upon the bushing and one side engaging theflange, an insulating washer slidable upon the bushing and engaging theother side of the pivot means, and a single operating means upon theclamp to grip the clamp on a pipe and to lock the pivot means.

13. A grounding system comprising a grounding fitting including clampingmeans to secure the grounding fitting to a grounded conductor, andanchorage means to secure an armored cable to the grounding fitting, anarmored cable secured at one end to the anchorage means and carryingaground wire electrically connected with the grounding conductor, andinsulated means between the anchorage means and the clamping meansthereby breaking electrical connection therebetween.

14. A grounding system comprising a grounding fitting including clampingmeans to secure the grounding fitting to a grounded conductor, andanchorage means to secure an armored cable to the grounding fitting, anarmored cable secured at one end to the anchorage means and carrying aground wire electrically connected with the grounding conductor, theother end of the armor of the armored cable being electrically connectedto the ground wire, and insulating means between the anchorage means andthe clamping means thereby breaking electrical connection therebetween.

15. A grounding system comprising a grounding fitting including clampingmeans to secure the grounding fitting to a grounded conductor, andanchorage means to secure an armored cable to the grounding fitting, anarmored cable secured at one end to the anchorage means and carrying aground wire secured to and electrically connected with the clampingmeans, the other end of the armor of the armored cable beingelectrically connected to the ground wire, and insulating means betweenthe anchorage means and the clamping means thereby breaking electricalconnection therebetween.

16. A grounding device comprising a rigid member having a seat portionfor engaging a grounded conductor and having an opening arranged at eachside 01' the seat portion, a U-shaped member for encircling the groundedconductor and havlng the ends of its branches extending through the 0enin'gs in the first member, a third member liaving an annular portionfor receiving the end of an electrical conduit and having a portionoverlapping one end of the first member and being provided with apassage for receiving one branch of the U-shaped member, the U- shapedmember having means for clamping the first and third members together inany of a plurality of angular ositions and for clamping the first memJer against the grounded conductor.

In testimony whereof I afiix In si ature.

STEPHEN N. BUG A AN.

